[Ovirt-devel] [PATCH] Add trivial error() function and change code to use it

[Jim Meyering]

"Perry N. Myers" <pmyers at redhat.com> wrote:
> Jeff Schroeder wrote:
>> Remove the multiple echo ... && exit 1 references and replace
>> them with a simple function. This makes the code a bit cleaner.
>
> No problem with this patch in concept, but this patch appears to be
> against the old repository.  See the instructions on:
> http://ovirt.org/build-instructions.html
>
> for getting access to the new repositories.
>
> The file you're patching is now located in the ovirt-server repository
> and it's location is:
>
> scripts/ovirt-server-install

...
>>  +error() {
>> +    echo $* >&2
>> +    exit 1
>> +}

Hi Jeff,

Thanks for the clean up.

However, the above use of $* is underquoted.
Here are a couple examples of what can go wrong:

  shell tokenization
    $ bash -c 'error() { echo $*; }; error "a          b"'
    a b

  ok when no file matches the "a*" glob:
    $ bash -c 'error() { echo $*; }; error "a*"'
    a*

  but when one does, ...
    $ touch a-file
    $ bash -c 'error() { echo $*; }; error "a*"'
    a-file

So, please use something like the existing "die",
which also prints the usual "$program_name: " prefix.

The following appears in several files:

  ME=$(basename "$0")
  warn() { printf "$ME: $@\n" >&2; }
  die() { warn "$@"; exit 1; }

But I've just realized that's not quite correct, in case $ME or $@ ever
expand to something containing a % (or, far less likely, a \c sequence
that printf recognizes), so this is better:

  ME=$(basename "$0")
  warn() { printf '%s: %s\n' "$ME" "$*" >&2; }
  die() { warn "$@"; exit 1; }

For the record, none of our existing uses of warn or die
would trigger the malfunction.

I've just posted a patch to fix those warn definitions.

paranoid^W defensively, ...
Jim